Datenbank beschreibenDESCRIBE DATABASE

DESCRIBE DATABASE die-Anweisung gibt die Metadaten einer vorhandenen Datenbank zurück.DESCRIBE DATABASE statement returns the metadata of an existing database. Zu den Metadateninformationen zählen Datenbankname, Daten Bank Kommentar und Daten Bank Speicherort im Dateisystem.The metadata information includes database name, database comment, and database location on the filesystem. Wenn die optionale- EXTENDED Option angegeben wird, werden die grundlegenden Metadateninformationen zusammen mit den Daten Bank Eigenschaften zurückgegeben.If the optional EXTENDED option is specified, it returns the basic metadata information along with the database properties. DATABASEUnd SCHEMA sind austauschbar.The DATABASE and SCHEMA are interchangeable.

SyntaxSyntax

{ DESC | DESCRIBE } DATABASE [ EXTENDED ] db_name

ParameterParameters

  • db_name: der Name einer vorhandenen Datenbank oder ein vorhandenes Schema im System.db_name: The name of an existing database or an existing schema in the system. Wenn der Name nicht vorhanden ist, wird eine Ausnahme ausgelöst.If the name does not exist, an exception is thrown.

BeispieleExamples

-- Create employees DATABASE
CREATE DATABASE employees COMMENT 'For software companies';

-- Describe employees DATABASE.
-- Returns Database Name, Description and Root location of the filesystem
-- for the employees DATABASE.
DESCRIBE DATABASE employees;
+-------------------------+-----------------------------+
|database_description_item|   database_description_value|
+-------------------------+-----------------------------+
|            Database Name|                    employees|
|              Description|       For software companies|
|                 Location|file:/you/Temp/employees.db  |
+-------------------------+-----------------------------+

-- Create employees DATABASE
CREATE DATABASE employees COMMENT 'For software companies';

-- Alter employees database to set DBPROPERTIES
ALTER DATABASE employees SET DBPROPERTIES ('Create-by' = 'Kevin', 'Create-date' = '09/01/2019');

-- Describe employees DATABASE with EXTENDED option to return additional database properties
DESCRIBE DATABASE EXTENDED employees;
+-------------------------+---------------------------------------------+
|database_description_item|                   database_description_value|
+-------------------------+---------------------------------------------+
|            Database Name|                                    employees|
|              Description|                       For software companies|
|                 Location|                file:/you/Temp/employees.db  |
|               Properties|((Create-by,kevin), (Create-date,09/01/2019))|
+-------------------------+---------------------------------------------+

-- Create deployment SCHEMA
CREATE SCHEMA deployment COMMENT 'Deployment environment';

-- Describe deployment, the DATABASE and SCHEMA are interchangeable, your meaning are the same.
DESC DATABASE deployment;
+-------------------------+------------------------------+
|database_description_item|database_description_value    |
+-------------------------+------------------------------+
|            Database Name|                    deployment|
|              Description|        Deployment environment|
|                 Location|file:/you/Temp/deployment.db  |
+-------------------------+------------------------------+